Expandable Choke Valve Stem Tip for Secure Head Locking
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Solution Overview
Problem
Adjustable choke valves in industrial and oilfield applications often experience valve stem head breakage or loosening, leading to improper operation and the need for frequent replacements.
Innovation Solution
A valve stem design featuring an expandable tip that radially expands upon insertion into the valve stem head, securing the valve stem body to the head and preventing inadvertent loosening or disconnection, utilizing a segmented tip with slots and a spherical insert to ensure a secure fit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a traditional valve stem head is brazed to the valve stem body, then the connection is strong, but the valve stem head may still break or become loose during operation
Solution Approach 1:
The valve stem tip is designed to change state from compressible to incompressible when pressurized by fluid flow. In normal operation, the compressible tip allows for thermal expansion and contraction without compromising the connection. When fluid pressure is applied, the tip becomes incompressible, locking the valve stem head securely to the body, preventing loosening or breakage during operation.
Solution Approach 2:
The connection mechanism changes its physical parameters based on fluid pressure. The valve stem tip transitions from a compliant state (allowing for assembly and thermal movement) to a rigid locked state under operating pressure. This parameter change ensures the connection remains secure during operation while allowing for manufacturing tolerances and thermal effects during assembly.
2Reliability
If the valve stem head is securely connected to prevent loosening, then connection reliability improves, but the device complexity increases
Solution Approach 1:
The locking mechanism is merged with the valve stem tip itself, which is already a necessary component for fluid flow control. The tip serves dual functions: regulating flow through the valve and providing the locking mechanism that secures the valve stem head to the body. This integration eliminates the need for separate locking components, reducing overall device complexity while maintaining high connection reliability.
Solution Approach 2:
The valve stem tip performs multiple functions simultaneously: it controls fluid flow through the valve, acts as a seal, and provides the locking mechanism that prevents the valve stem head from loosening or breaking. This multi-functionality reduces the number of separate components needed, simplifying the overall valve stem structure while ensuring reliable connection.
3Reliability
If a complex locking mechanism is used to prevent valve stem head failure, then connection reliability improves, but the ease of manufacture decreases
Solution Approach 1:
The valve stem tip is segmented into multiple sections that can be independently manufactured and then assembled. This segmentation allows each section to be produced using standard manufacturing processes without requiring complex tooling or specialized techniques. The segmented design simplifies manufacturing while the assembled structure provides the reliable locking connection when pressurized.
Solution Approach 2:
The locking mechanism is self-activating through the natural pressure differential that exists during valve operation. The fluid pressure automatically compresses the tip, triggering the locking action without requiring external actuators, motors, or additional control systems. This self-service mechanism eliminates complex manufacturing requirements while ensuring the connection locks reliably under operating conditions.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The design effectively secures the valve stem head to the body, preventing accidental loosening and reducing the need for frequent replacements, ensuring reliable operation and flow regulation in choke valves.
Implementation Method 1
An insert will engage the expandable tip and will be pressed into the opening therein to expand the tip radially outwardly
Implementation Method 2
In the radially expanded position the segments of the valve stem tip are bent radially outwardly to an outer dimension or outer diameter that is greater than the diameter of the entry opening
Data Source
AI summary
A valve stem includes a valve stem body connected to a valve stem head. The valve stem is for use with a choke valve. The valve stem body has first and second ends with an expandable valve stem tip extending from the second end of the valve stem body. The valve stem tip expands radially outwardly in an opening in the valve stem head to secure the valve stem head to the valve stem body.